In the conventional treatment of broken bones, it is the usual practice to manually adjust the bone fragments, secure them in a fixed relation by the use of splints, and thereafter encase the broken limb in a plaster cast. This method requires that the limb be very carefully guarded because of the danger of disturbing the alignment of the bone fragments. In addition, the use of a plaster cast precludes treatment of any flesh wounds which may have occurred adjacent the fracture.
The treatment of a patient with an open fracture and severe soft-tissue damage presents significant problems. As discussed in "Salvage of Complicated Open Fractures by Transfixation" in the Journal of Trama, Vol. 16, No. 4, Pages 266 to 272 (1976) by E. B. Weis, Jr., J. B. Roberts, and P. A. Curtis, Jr., the patient with an open fracture of the shaft of the tibia with skin lost is one common example of this problem. One is reluctant to stabilize the open fracture with an implant and skin loss makes this even less attractive. Such a fracture has absolutely no inherent stability and a cast often cannot be applied with good position or alignment. When arterial injuries are present, the instability causes some concern for the graft or repair. As a result of these problems, this article proposes a method of transfixation making use of a Reduction-Retention apparatus manufactured by the Zimmer Company, Warsaw, Ind. Transfixation is a general name for methods of immobilization of fractures in long bones in which pins or screws are passed through the skin into the fragments and immobilized with extra cutaneous plaster, plastic, or metal apparatus.
The Zimmer Reduction-Retention apparatus disclosed in this article includes a central threaded compression rod on which two collars are mounted between locking nuts. The collars have extensions to which ball joint mechanisms are mounted including outwardly extending bars on which pin clamping means are provided. Set screws are provided along the proximal ends of the collars which are locked in place to hold the bars stationary. The distance between the collars is then adjusted by movement of the collars along the compression rod.
In use, the Zimmer Reduction-Retention apparatus is applied as follows. Initially, a percutaneous approach is used unless the bone is exposed by the soft-tissue injury. Thus, the apparatus is placed by making a stab incision in the skin over the location where the pin is to be placed. A trocar is then passed through this wound, impacted gently on the bone, and held in place. A drill is passed throught this trocar and through both cortices, and the pin is passed through the same trocar and screwed into the bone until the second cortex is firmly engaged. The trocar is removed and the procedure is repeated until there are two pins in each bone fragment. The pins should be reasonably well aligned with each other and with the long axis of the bone, but the pins need not be perfectly aligned. The clamp means located on the rods are then passed over respective pins with the set screws of the ball joint completely loose. The clamp means screws are then tightened. Next, the compression rods and its nuts are loosened and the handles are placed in the end of the ball joint devices. The fractured bones are then manipulated into correct alignment with these handles and the ball joint set screws tightened with the wrench. The nuts and the compression rod are then advanced to tightly lock the collars in place.
Various other external fixation devices have been disclosed in the prior art. For example, pairs of pin engaging members which are interconnected by adjustable struts having universal ball mountings to the members are disclosed in the following U.S. Pat. Nos. 2,238,869 (Haynes), 2,238,870 (Haynes), and 4,312,336 (Danieletto et al). A simple turnbuckle type mechanism for drawing two bones together by use of pins is disclosed in U.S. Pat. No. 1,997,466 (Longfellow). A turnbuckle and universal ball mounted tool used to reduce bone fragments is also disclosed in U.S. Pat. No. 2,631,585 (Siebrandt). Various outher fixation apparatus including adjustable slide mechanisms and universal mountings are disclosed in the following U.S. Pat. Nos. 4,135,505 (Day), 4,258,708 (Gentile), 4,127,119 (Kronner), 4,299,212 (Goudfrooy), and 4,273,116 (Chiquet).
Although external fixation devices have been disclosed in the prior art, the devices are often cumbersome and difficult to use. In addition, these devices require precise pin placements which may not always be possible because of the fracture site.